(a) Field of the Invention
The present invention relates to a stator for a synchronous motor, and more particularly, to a stator for a synchronous motor, which is used as a power source for an electric vehicle and a hybrid vehicle.
(b) Description of the Related Art
In general, a synchronous motor that is a power source for hybrid and electric vehicles includes a stator, and a rotor. The stator is fixed to a periphery of the rotor. In addition, the rotor is rotated to output power of the synchronous motor to the exterior. Moreover, the stator transmits rotational force to the rotor to rotate the rotor. The rotor is formed in a cylindrical shape, and the stator is formed in a hollow cylindrical shape. In addition, the rotor is inserted into a hollow portion of the stator.
Armature coils are disposed at the stator in a circumferential direction of the stator, and permanent magnets are disposed at the rotor in a circumferential direction of the rotor. In addition, the rotor is rotated as the permanent magnets are pushed in one direction by magnetic fields formed at the armature coils. Moreover, functions of the synchronous motor may be changed based on configurations of the armature coils and the permanent magnets.
When a current is applied to the armature coils, the armature coils become electromagnets. Therefore, torque of the synchronous motor is produced by attractive force and repulsive force between the armature coils and the permanent magnets by north (N) poles and south (S) poles of the armature coils, which became electromagnets, and the permanent magnets.
A winding wire path of the armature coil provided at the stator configures a series circuit or a parallel circuit based on a design of the synchronous motor. In addition, a direction of the current, which flows along the winding wire path of the armature coil, may be reversed to generate an alternating magnetic field by the stator. Meanwhile, a type of winding of the armature coil includes a fractional pitch winding using a coil wherein the pitch between two sides thereof is shorter than one magnetic pole pitch, and a full pitch winding using a coil wherein the pitch between two sides thereof is the same to one magnetic pole pitch. In the winding of the armature coil of the related art, in/out direction of the coil is set to generate the alternating magnetic field by a predetermined rule.
However, the winding of the armature coil in which the in/out direction is set as described above may excessively raise resistance of a phase drawing out unit of the armature coil. In addition, resistance imbalance of the armature coil may be caused.
The above information disclosed in this section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.